Longevity Genes Predict Whether You'll Live Past 100

Reaching immortality is still in the realm of science
fiction. But using clues from our genes, scientists are one step closer to
understanding why some of us live to be centenarians while others don't.

Using a specific set of genetic markers, scientists predicted
with 77-percent accuracy whether someone would live to a very old age.

The findings do not mean that lifestyle factors, such as healthy
diet and exercise, are not important for long life. Indeed, 23 percent of
the time the genetic markers didn't predict longevity. So those long-lifers without
the centenarian genes might have practiced healthy habits that allowed them to
lead a longer
life. [Learn more facts about centenarians]

But they do suggest our genes play an important role when it
comes to living well past the average lifespan. With more research, one day
people might be able to determine whether they have the genetic potential to
become a centenarian.

Additionally, learning more about how centenarians ward off
diseases, including dementia, heart disease and cancer, well into their elder
years, might help the rest of us delay disease.

"I'm very hopeful that understanding how and why centenarians
are able to do that will lead to strategies and therapies, including screening
and figuring out who could be helped by whatever therapies [there] are down the
road," study researcher Tom Perls, of Boston University School of Medicine,
said in a press briefing Wednesday about the study.

The results will be published this week in an early online
edition of the journal Science.

Longevity genetics

The researchers compared the genomes of 1,055 centenarians
(average age of 103) with those of non-centenarian controls.

They identified differences in the genetic code, known
as genetic variants or markers, that were common in centenarians but not in the
average population.

Using a computer model, they found 150 of these markers
could predict 77 percent of the time whether a person lived into their late 90s
and beyond.

Additionally, they saw 90 percent of the centenarians could
be categorized into one of 19 groups based on which genetic variants they had.
In other words, each group had a distinguishing "genetic signature"
made up of certain genetic markers.

Differences in these genetic signatures may relate to differences
in the way extreme longevity manifests itself. For instance, some genetic
signatures were associated with extremely old age (living 110 years or more), while
others were associated with a late onset of diseases such as dementia.

So can someone live to old age without these markers?
Perhaps. About 30 of the centenarians had almost none of the longevity
associated markers. In these cases, extreme old age might be influenced by other
markers that have yet to be identified, or by the subject's lifestyle.

The researchers were also curious if centenarians had fewer
markers that are known to be linked with diseases. However, in this respect,
they found little difference between the centenarians and the control group.

This might mean that centenarians owe their exceptional
lifespan not to less "bad genes," but to the presence of "good
genes" that override the harmful ones.

This results suggests "that what makes people live very
long lives is not a lack of genetic predispositionto diseases, but rather an arrangement of
longevity associated variants that may be protective, it may even cancel the
negative effect of disease-associated variants," said study researcher Paola
Sebastiani, of Boston University School of Public Health, who also spoke at the
briefing.

Future outlook

The researchers caution that before a genetic test for
longevity is developed, scientists need to have a better understanding of what
kind of effect the information could have on society, such as in the context of
health care.

They hope the study spurs additional research into these
genetic markers and how they might biologically contribute to longevity.

"I think that we're quite a ways away still in understanding
what pathways governed by these genes are involved, and how the interaction of
these genes, not just with themselves, but with environmental factors, are all
playing a role in this longevity puzzle," Perls said.

The study was funded by grants from the National Institute
of Aging (NIA) and the National Heart Lung and Blood Institute (NHLBI) of the
National Institutes of Health (NIH).

Rachael Rettner

Rachael has been with Live Science since 2010. She has a masters degree in journalism from New York University's Science, Health and Environmental Reporting Program. She also holds a Bachelor of Science in molecular biology and a Master of Science in biology from the University of California, San Diego.